ixeg 737 takeoff runway lengths.... KSNA takeoff didnt go well!

[wiler 394]

Does anyone know where to find a take off runway length calculator for this bird? Took off from KSNA  (apprx 5200 ft) yesterday w flaps 15 and used up all the runway and then a little more :( I was probably a bit too heavy .... I cant find it in the docs that come with the aircraft, ive also googled it but haven't found anything. 

[Janov 2,383]

I am sure you can find some runway weight charts around... but these are not so easy to read and use. Nowadays we do performance calculation on laptops or EFBs...

 

As a ballpark figure you can assume that all runways above 7000 feet (ca. 2100m) are ok for takeoffs and landings at maximum weight, unless you experience very unusual environmental parameters (density altitude, slippery runway).

 

Anything below 6000 feet (ca. 1800m) is only for favourable conditions, and the shortest I would use is maybe 5000 feet (1500m), but this is only for very good conditions (light aircraft, dry runway, good headwind).

 

This is not scientific, just my gutfeeling after flying that bird for a few thousand hours...

 

Jan

[wiler 394]

Thanks for the tips, Ive seen some amazing vids of take offs with 737C/737NG even 757s from orange county, my GW was around 60t for my failed takeoff , maybe was just a bit too heavy... 

I am sure you can find some runway weight charts around... but these are not so easy to read and use. Nowadays we do performance calculation on laptops or EFBs...

 

As a ballpark figure you can assume that all runways above 7000 feet (ca. 2100m) are ok for takeoffs and landings at maximum weight, unless you experience very unusual environmental parameters (density altitude, slippery runway).

 

Anything below 6000 feet (ca. 1800m) is only for favourable conditions, and the shortest I would use is maybe 5000 feet (1500m), but this is only for very good conditions (light aircraft, dry runway, good headwind).

 

This is not scientific, just my gutfeeling after flying that bird for a few thousand hours...

 

Jan

[Janov 2,383]

Ermm, isn´t there a long, big runway at KSNA? I made the airport for XP, and I sure remember it having one long and one small runway...

 

Edit: Yeah, its 5700 feet, so it should be ok for taking off in a fully loaded 737 unless its really hot or the wind is a tailwind...

[sizziano 172]

Ermm, isn´t there a long, big runway at KSNA? I made the airport for XP, and I sure remember it having one long and one small runway...

 

2L/20R is 5,700 feet and is the longest there.

[mwilk 1,106]

Gave it a try in XP11. Runway 02 the IXEG was loaded to 61 tonnes. Trim set at 3.5 and flaps 5. I was able to get off of the ground with plenty of runway to spare.

[wiler 394]

what was your n1 %? i tried again at 55t  flaps 15 vr was only 135 ish and still didnt make it in time....

Gave it a try in XP11. Runway 02 the IXEG was loaded to 61 tonnes. Trim set at 3.5 and flaps 5. I was able to get off of the ground with plenty of runway to spare.

[mwilk 1,106]

what was your n1 %? i tried again at 55t  flaps 15 vr was only 135 ish and still didnt make it in time....

Tried it again. I had a gross weight of 147,000 lbs. At flaps 5 and trim of 3.6 I had a %of N1 of 90.1. I was still able to get off the ground with some room to spare. It did climb like a wounded duck. I rotated at about 125kts.

[wiler 394]

something doesnt sound right, 124k vr w flaps 5? cant be.....even with flaps 15 the fmc is telling me 135 and that with less wieght then you say you had. 

Tried it again. I had a gross weight of 147,000 lbs. At flaps 5 and trim of 3.6 I had a %of N1 of 90.1. I was still able to get off the ground with some room to spare. It did climb like a wounded duck. I rotated at about 125kts.

[sizziano 172]

what was your n1 %? i tried again at 55t  flaps 15 vr was only 135 ish and still didnt make it in time....

Are you derating the engines?

[Janov 2,383]

something doesnt sound right, 124k vr w flaps 5? cant be.....even with flaps 15 the fmc is telling me 135 and that with less wieght then you say you had. 

 

The maximum takeoff weight for a 737-300 is around 132,000 lbs. We allow to load the plane more (to try it out) - but don´t be surprised if perfomance suffers from that.

[wiler 394]

not on purpose! 

Are you derating the engines?

n1 91,8 20k thrust. 

not on purpose! 

i loaded to around 110,000 91.8 n1 and still cant get off in time, its close but still too long. 

The maximum takeoff weight for a 737-300 is around 132,000 lbs. We allow to load the plane more (to try it out) - but don´t be surprised if perfomance suffers from that.

[mwilk 1,106]

The maximum takeoff weight for a 737-300 is around 132,000 lbs. We allow to load the plane more (to try it out) - but don´t be surprised if perfomance suffers from that.

Many moons ago, I used to do weight and balance on 737-300 for US Air. I knew 147k had to be over MTOW but I couldn't remember what it was. The way it was explained to me, the MTOW was calculated for an engine failure at VR and still be able to get airborne. The actual weight that the aircraft would take off at with both engines was much higher.

[Janov 2,383]

Well, there is a structural MTOW for 737-300, it is usually 56.700 kgs or 125.000 lbs. There are variants (freighter, Quickchange) that can have a higher MTOW, up to 60.000kgs (132.000lbs).

 

The PTOW (performance take off weight) may be much lower, and depends on runway length and environmental factors. Without going into take-off performance calculation, it would need to be low enough so you can both accelerate to liftoff if an engine fails at V1 or stop on the remaining runway if an engine fails at V1. So a slippery runway may be a problem (braking is hard) as could be an obstacle at the runway end (that you need to be able to clear if flying on just one engine). Both cases need to be "balanced".

 

Jan

[Janov 2,383]

...and I just tried myself in XP11.

 

At 60.000kg TOW with no wind and a flaps 15 takeoff (V1 138, V2 145) at runway 20R I lifted off JUST past Echo taxiway. V1 was attained just past the PAPI installation for runway 02L - so with about 900 feet of runway left.

 

This is certainly not enough runway left to reject the takeoff, but taking off is possible. I would guess that the regular MTOW of 56.700 kg or 124.750 lbs is just about legal on a regular day.